Lining for tunnels and for shafts.



Patented Jan. 12, 1915.

2 SHEETSSHEET 1.

G. H. DUNLOP.

LINING FOR TUNNBLS AND FOR SHAFTS. APPLICATION FILED JUNE 29, 1914.

G. H. DUNLOP.

LINING FOR TUNNBLS AND FOR SHAFTS.

APPLICATION FILED JUNE 29, 1914.

Patented Jan. 12

' ZSHBETS-SHEET v STATES PATE T OFFICE.

GEORGE HENRY D'UNLOP, OF BRISBANE. QUEENSLAND, AUSTRALIA LINING FOR TUNNELS AND FOR SHAFTS.

To all whom it may concern:

Be it-known that I, GEORGE HnNRY DUN- nor, a subject of the King of Great Britain,

residing at Commercial Travellers Club, Elizabeth street, Brisbane, in] the State of Queensland and Commonwealth of Austral-ia, have invented a new and useful Improvement in Linings for Tunnels and for Shafts, of which the following is-a specification. i

This invention relates to linings employed to sustain the ground, in tunnels and in shafts, and more particularly in shielddriven tunnels, preparatory to the completion of'the work with final lining of masonry or the like; though of course it may i constitute the sole lining used where such masonry or the like is not desired.

Hereinafter the invention w ll be described as applied to a shield-driven tunnel of circular form.

The lining is composed of sections which will be called segments, which may be either molded or built up, a suitable number of which in place will'form a ring constituting the completed'lining for a short length of tunnel, together with connecting ribs which form rings between and in conjunction with the segmental rings, the whole being fitted with. suitable flanges, cover plates, and joints, secured together with bolts or spikes, and provided with means for waterproofing the complete work when required;v all of which are shown in the accompanying drawings in which Figure 1 is a part longitudinal sectional elevation of a tunnel'lining with molded segments and in which the shield is shown in outline. -Fig.- 2 is a part end elevation of Fig. 1 showing about one half of the clrcle, and also showing concrete placed w'ltllln the molded lining. Figs. 3 and 4 show details 7 of joints. Fig. 5 shows part of the lining 1 upon each other at longitudinal joints 0 0,;

completed with the waterproofing construe tion. Fig. 6 shows a part longitudinal sectional elevation and Fig.7 a part end elevation similar respectively to F lgs. 1 and 2 but with built-up wooden segments. Figs. 8, 9 and 10 show details ofthe construction in Figs. 6 and 7. In Figs. 1 and 2 a a are segments having circumferential flanges b b, s x segments forming the ring in the drawing, abutting and having between the adjacent circumfer ential flanges of the two rings shown in I Specification of Letters Patent.

Fig. 1, connecting ribs 03 (Z, three in number In the drawing, the flanges of the segmental rmgs and the connecting ribs being secured together with bolts as shown, the three-ply forming what I call a rib-ring. The connecting ribs are shown projecting outwardly the efliciency of the rib-ring against cross Patented Jan. 12, 1915.

' Application filed June 29, 1914. Serial No. 848,029.

breaking strain due to unequal loading.- i In Figs. 6 and 7 the segments a a are formed of wood each of two flanges or rib pieces as a a'- having nailed on to them logging or boarding as a" a covering the outer curve thereof, and six -of these builtgether byspikes. In Fig.8 opposite the joints of the connecting ribs (1 d,- outside of the flanges'of the segments, are shown metal cover plates f f, for the same purpose as the thicker-flangesof the molded segments already described.

In Fig. 6 struts are shown which assist in bearing and distributing the pressure of the rams used for forcing the. shield forward. These may be such as pieces of tim ber as g g.fitted with wedges as h h at the ends, or suitable screw jacks as 2'. The molded segments may be similarly equipped if necessary. It is desirable to leave few longitudinal joints in-each ring of lining. It is usually necessary however to have a considerable number of segments in the ring, so that each piece may be of convenient size, but as the connecting ribs can be handled more easily thenumber in the-ring can be reduced possibly to two, though usually it would be convenient to have at least three in each ring; and with connecting ribs of wood a still greater number may probably be required, otherwise the timber would be I it is customary to have the outer diameter of the linings smaller than the inner diameter of the shield, for one reason in order up segments form the ring as illustrated,

cent rib or flange pieces being' secured tothat the shield maybe moved more freely especially when its direction of progress is being changed. In order to. prevent this,

the ring of connecting ribs may be made equal to the inner diameter of the shield, while still leaving the shield as free from contact all around the lining as before except at the contact with the connecting ribs (which are narrow as compared with the segments of a ring), as soon as the tail end of it has passed the second last connecting ring in place, that is during. the greater part of the length which the shield is moved forward for each ring. If necessary the outside of the connecting ribs may be rounded for further convenience in this respect- In Figs. 1, 2, 6 and 7 the shield and the tunnel lining are shown as they usually are, circular in cross section, the inside diameter of the shield being slightly greater than the outside diameter of the lining, and with the lining built resting on the shield at the bottom,and with a space between at the top equal to the difference, of the diameters. The connecting ribs (1 d extend from the inside of the flanges of the segments out to contact or close fitting with the inside of the shield all around, owing to their being constructed wider at the top than at the bottom. -This gives greater strength to the rib-ring especially against bending strain, the close fitting will prevent the passage of fine material into the tunnel between the shield and the lining, and will also serve in the same way to retain grout when forced outside of the lining to fill void spaces without the usual contrivances required for this purpose. The connecting ribs act as cover plates at the joints of the segments, so as to increase the efliciency of the rib-ring against bending, and being few in number it becomes quite practicable to provide extra strength in the flanges or ribs at each side.

of the joints of the connecting ribs by increased thiclmess or by cover plates as already described. There being fewer connecting ribs than segments in the rings admits of the joints of these ribs being located more suitably relative to the seental joints, that is, they may be placed at those parts of the ring where the least tendency to cross bending is expected. When there are three connecting ribs in the ring, they may not-be all of equal length. One may be short, acting as a closing piece, and in this case the cooperating cover plates, or thicken flanges, may extend over the joints at both ends of such short connecting rib. With wooden connecting ribs, if it is not otherwise necessary that they should extend out to the 1 shield all around, the pieces may be cut from narrower planks, especially the top one, as shown at j. in Fig. 9 where the size of plank is shown by dotted lines, and the sizeof rib by full lines, the rib being deeper where it extends out to the shield near the ends and where also the her is weaker against cross breaking strain being cut partly across the grain. lit will be noted also that the rib piece of each wooden segment is not of as full radial depth at the ends as elsewhere. This small piece is liable to be split off and therefore an appreciable saving of timber may be effected by using a narrower plank without any appreciable .loss of strength.

Hitherto the smaller circular lining has been built within the larger circular shield without any convenient means for guiding the form of the lining, and usually the lower part-about one half--of the lining has been built upon the inside of the shield, and the upper remaining part has been built to close at the top. Thus an initial distort1on is given to the lining designed to be circular. With connecting ribs and segments in "combination according to this invention,

the connecting ribs being cut on the outside toconform, throughout the circle, or at least for a suflicient part of it, and on theinside to conform similarly with the inside of the flanges or ri'bs'oij the segments, the lining may be erected easily and true to form, the shield being used as a form for ad usting the connecting ribs, and then these as guldes for adjusting the segments. After the shield has been moved forwardthe requlslte distance, a ring of segments and a ring of connecting ribs following are placed in position within the rear end of the shield as shown in Figsd and 6, the segments are connected to the rings of segments and connecting ribs last placed, the three ply ribbeing finally secured together, and at the leading or. shield-ward end the ring of'segmental flanges or ribs and the connecting ribs are secured together sufhciently sothat this two-ply rib-ring may retain its form against such forces as may be applied, including the -pressure of therams when moving the shield forward again. i

The connecting ribs may project beyond the segments all around the lining, though it will usually be unnecessary that they should do so at the bottom.

lit has been the practice with molded linings such as cast iron, to have longitudinal flanges as well as and similar to the circumferential flanges shown herein, each segment being in fact a hollow voussoir (see Fig. 3).; all contiguous flanges being bolted together so as to render the ring capable of bearing unequal loading around the ring. lhese longitudinal flanges may be employed with ments are molded-of more bulky material than cast iron, as for example of concrete or the ring, and as far as I know'have always been made straight. With the present linings the longitudinal joints, especially with cast or molded parts, may be curved, as at k in Fig. 3, so that the parts may accommodate themselves to slight deflections of the rings; and such curve may be a circular are having airadius' equal to the chord length of the part of the ring forced by the piece to have the concave curved joint. Other forms-of curve may be chosen however. The abutting lagging of wooden segments need not be curved because the swelling of the timber when placed in the ground will accommodate any slight irregularities of fitting. The abutting ends of wooden ribs are not shown curved in the drawing because it is not considered that this will be necessary with wooden ribs properly fitted and secured together as shown and described; but of course they may be curved.

Molded linings may be secured together by bolts passing through holes sufliciently larger than the bolts to permit easy erection, and of subsequent packing as at Z Z, in Fig. 4, of the surplus space, before the nut is screwed on. Metallic packings, aslead, may be used with metallic linings as cast iron; and cement mortar may be used with concrete linings. Rivets of course would be preferable in any case where they could be used.

When the ribs of linings are formed wholly or mainly of wood, in two or more layers in the rib-ring, then as shown in Fig. 10, spikes or nails m such as Ewbanks may be used for securing the layers together and of a length suitably greater than the combined thickness of the rib, layers through which they are driven, so that the endsmay' be turned over and clenched as at m In this way the rib pieces are held more securely together, and so that as the timber absorbs moisture when in place in the ground, the swelling of the timber, so con-- nected, forces the rib pieces together, thereby making the construction closer and tighter, the nails or s ikes m holding the pieces more firmlyby ing clenched as at m than they would otherwise do, and thusconnecting ribs will not present and effectively held on to the ribs when desired. i

In Fig. 5 there is shown in part a construction having the moldedsegments and connecting ribs of concretewithin which,

there is applied a layer of cement mortar,

as 0, 0, applied 'to the inner surface of the segments and connecting ribs, and thoroughly compressed to make it compact and waterproof, and within this waterproof "In Fig. 5 the segmental lining. is shown,

' layer there is built further concrete lining as p The water, if necessary,

adapted to transmit loading by acting as anarch abutting on the connecting rib and at the same time being rounded inside 0on 'veniently for receiving the waterproofing coating. The connecting ribs may then be made specially strong so as to bear much of the loading primarily coming upon the segments-and thence transmitted to the ribs;

Any suitable jointing material may be used,

last piece may be placed by the following procedure: Approximately place all segments except the last, pushing them all out against the shield so as to leave the space for placing the last one as large as possible. Raise the last segment required to complete the ring drawn forward shield-ward slightly more than the thickness of the circumferential flange or rib that is until this rib is occupying approximately the position after-' ward to be filled by the connecting ribplace one end of said last segment against the segment against which it is to abut on completion, then swing the other end of the said last segment up, push it back, and adjust the whole finall The 'flicnlty with all radial joints since the rams on the shield can if necessary be adaptgd to 've clearance for the last piece to raise in advance of its final position and then pushed back.

While .cast iron and reinforced concrete are probably the best materials for molded segments, and rolled steel and reinforced concrete for connecting, ribs therewith respectively, and timber will be best for builtup segments and connecting ribs therewith,

The lining according to this invention is applicable with evident modifications, in tunnels Where the shield is not used Where the groundis sufliciently firm to s'tand unsupported for the length and for the time necessary for inserting a ring of the segmental lining and of connecting ribs, or if the ground is WhOllYOI partially supported by compressed air, or by temporary timbering or the like. And the lining may be applied in shaft sinking in a similar manner to that described for tunneling, With or without a shield or box in advance.

What I claim as my invention, and desire to secure by Letters Patent is 1. Linings for tunnels constructed of segments forming rings built Within the shield and. eccentric to it together with rings of connecting ribs concentric with the segmental rings on the inside and on the outside concentric with the inside of the shield.

2. Linings for tunnels comprising segmental rings having ribs or flanges com bined with connecting ribs which lie between the ribs or flanges of the segmental rings and fit neatly and. concentric in part Within the shield while the segmental linings are of a lesser diameter than and lie eccentric within the shield.

In testimony whereof I have signed by name to this specification in the presence of tWo subscribing witnesses. I

GEORGE HENRY DUNLQP. Witnesses:

PERCY NEWELL, H. R. HILL. 

